Method for transferring light emitting elements, display panel, method for making display panel, and substrate

ABSTRACT

A method for transferring light emitting elements precisely during manufacture of display panels includes providing light emitting elements; providing a first electromagnetic plate defining magnetic adsorption positions; providing a receiving substrate defining receiving areas; providing a second electromagnetic plate; energizing the first electromagnetic plate to magnetically adsorb one light emitting element at one adsorption position; providing a second electromagnetic plate; and transferring the light emitting elements to one receiving area of the receiving substrate.

FIELD

The subject matter herein generally relates to display field, andparticularly relates to a method for transferring light emittingelements, a display panel, a method for making the display panel, and asubstrate.

BACKGROUND

The size of a light emitting element such as light emitting diode (LED)generally tends towards smaller size, as a result, transferring a largenumber of light emitting elements to a receiving substrate ischallenging.

Therefore, there is room for improvement in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present disclosure will now be described, by wayof embodiment, with reference to the attached figures.

FIG. 1 is a flow chart of a method for transferring light emittingelements.

FIG. 2 is a cross-sectional view illustrating the light emittingelements during Block S11 of the method as disclosed in FIG. 1.

FIG. 3 is a cross-sectional view illustrating the first electromagneticplate during Block S12 of the method as disclosed in FIG. 1.

FIG. 4 is a cross-sectional view illustrating the receiving substrateduring Block S13 of the method as disclosed in FIG. 1.

FIG. 5 shows a receiving substrate of FIG. 4 made according to themethod.

FIG. 6 shows projections of an electromagnetic unit and a receiving areaof the receiving substrate shown in FIG. 4.

FIG. 7 shows projections of the electromagnetic unit and the receivingarea of the receiving substrate shown in FIG. 4 according to anotherembodiment.

FIG. 8, FIG. 9, and FIG. 10 are cross-sectional views illustrating theresults during Block S14 of the method as disclosed in FIG. 1.

FIG. 11 is a cross-sectional view illustrating the result during BlockS15 of the method as disclosed in FIG. 1.

FIG. 12 and FIG. 13 are cross-sectional views illustrating the resultsduring Block S16 of the method as disclosed in FIG. 1.

FIG. 14 is a flow chart of a method for making a display panel.

FIG. 15 is a cross-sectional view illustrating the result during BlockS27 of the method as disclosed in FIG. 14.

FIG. 16 is a cross-sectional view illustrating the result during BlockS28 of the method as disclosed in FIG. 14

FIG. 17 is a cross-sectional view illustrating the result during BlockS29 of the method as disclosed in FIG. 14.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the exemplary embodiments described herein.However, it will be understood by those of ordinary skill in the artthat the exemplary embodiments described herein may be practiced withoutthese specific details. In other instances, methods, procedures, andcomponents have not been described in detail so as not to obscure therelated relevant feature being described. Also, the description is notto be considered as limiting the scope of the exemplary embodimentsdescribed herein. The drawings are not necessarily to scale and theproportions of certain parts may be exaggerated to better illustratedetails and features of the present disclosure.

The term “comprising” when utilized, means “including, but notnecessarily limited to”; it specifically indicates open-ended inclusionor membership in the so-described combination, group, series, and thelike. The disclosure is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that referencesto “an” or “one” embodiment in this disclosure are not necessarily tothe same embodiment, and such references can mean “at least one”. Theterm “circuit” is defined as an integrated circuit (IC) with a pluralityof electric elements, such as capacitors, resistors, amplifiers, and thelike.

Referring to FIG. 1, a flowchart of a method for transferring lightemitting elements in one embodiment is disclosed. The method is providedby way of embodiment, as there are a variety of ways to carry out themethod. The method described below can be carried out using theconfigurations illustrated in FIGS. 2 through 13 for example, andvarious elements of these figures are referenced in explaining themethod. Each block in this method represents one or more processes,methods, or subroutines, carried out in the method. Additionally, theillustrated order of blocks is by example only and the order of theblocks can change. The method can begin at Block S11.

Block S11: a plurality of light emitting elements 10 as shown in FIG. 2is provided.

As shown in FIG. 2, the light emitting elements 10 are spaced apart fromeach other on a carrier substrate 20. Each light emitting element 10includes a P-type doped inorganic light-emitting material layer 12, anN-type doped inorganic light-emitting material layer 14, and an activelayer 13 between the P-type doped inorganic light-emitting materiallayer 12 and the N-type doped inorganic light-emitting material layer14.

In one embodiment, the carrier substrate 20 is a growth substrate, suchas sapphire or the like. In other embodiments, the carrier substrate 20is a platform for placing the light emitting elements 10.

In one embodiment, opposite ends of each light emitting element 10 areprovided with a first electrode 11 and a second electrode 15. The firstelectrode 11 and the second electrode 15 may be made of a first magneticmaterial layer 16 of opposite magnetic properties. The P-type dopedinorganic light-emitting material layer 12 is electrically connected tothe first electrode 11, and the N-type doped inorganic light-emittingmaterial layer 14 is electrically connected to the second electrode 15.That is, the first electrode 11 and the second electrode 15 aredifferent poles with opposite magnetism. For example, the magnetic poleof the first electrode 11 is N pole, the magnetic pole of the secondelectrode 15 is S pole, or the magnetic pole of the first electrode 11is S pole and the magnetic pole of the second electrode 15 is N pole.

In another embodiment, the first magnetic material layer 16 is not usedas an electrode of the light emitting element 10. The first electrode 11and the second electrode 15 of each light emitting element 10 areprovided with a first magnetic material layer 16 of opposite magneticproperties.

In yet another embodiment, only the first electrode 11 or only thesecond electrode 15 of each light emitting element 10 is provided withthe first magnetic material layer 16. One end of each light emittingelement 10 having the first magnetic material layer 16 is arranged toface upward on the carrier substrate 20.

In one embodiment, the first magnetic material layer 16 may be made of amagnetic material, such as an aluminum-nickel-cobalt permanent magnetalloy, an iron-chromium-nickel permanent magnet alloy, a permanentmagnet ferrite, other rare earth permanent magnet materials, or acomposite permanent magnet material composed of the above materials.

In one embodiment, the light emitting element 10 is a conventional lightemitting diode (LED), mini LED, or micro LED. “Micro LED” means LED withgrain size less than 100 microns. The mini LED is also a sub-millimeterLED, and its size is between conventional LED and micro LED. “Mini LED”generally means LED with grain size of about 100 microns to 200 microns.

Block S12: a first electromagnetic plate 30 as shown in FIG. 3 isprovided.

The first electromagnetic plate 30 may be made of a material beingmagnetic when energized and having no magnetism when not energized. Asshown in FIG. 3, an insulating nonmagnetic material layer 31 is on asurface of the first electromagnetic plate 30. The insulatingnonmagnetic material layer 31 defines through holes 33 spaced apart fromeach other, and the surface of the first electromagnetic plate 30 isexposed from the through holes 33. Each through hole 33 is defined asone adsorption position 32. Each adsorption position 32 is capable ofmagnetically attracting one light emitting element 10 on beingenergized. The adjacent through holes 33 are spaced apart from eachother by the insulating nonmagnetic material layer 31.

When the first electromagnetic plate 30 is energized, the positions ofthe through holes 33 (i.e., the exposed surface of the firstelectromagnetic plate 30) magnetically adsorb the first magneticmaterial layer 16 at one end of the light emitting element 10, therebypulling one of the light emitting elements 10 into one of the throughholes 33. Other positions do nothing. That is, when the firstelectromagnetic plate 30 is energized, only the positions correspondingto the through holes 33 have magnetic properties. A size of each throughhole 33 is slightly larger than the size of the light emitting element10, each of the through holes 33 can adsorb only one of the lightemitting elements 10.

In one embodiment, the insulating nonmagnetic material layer 31 may bemade of a polyimide-based composite material.

In one embodiment, a mechanical arm (not shown) is further provided on aside of the first electromagnetic plate 30 away from the insulatingnonmagnetic material layer 31 to grasp and manipulate the firstelectromagnetic plate 30, up and down and to either side.

In one embodiment, a control circuit (not shown) is further providedcorresponding to the first electromagnetic plate 30. The control circuitis configured to supply a voltage or current to the firstelectromagnetic plate 30 to energize the plate 30 and make it magnetic.In addition, a magnetic strength of the first electromagnetic plate 30can be controlled by adjusting a magnitude of the voltage or currentapplied to the first electromagnetic plate 30 by the control circuit.

Block S13: a receiving substrate 40 is provided.

The receiving substrate 40 as shown in FIG. 4 includes a base layer 41,a second magnetic material layer 43 on a side of the base layer 41, anda bonding layer 45 on a side of the second magnetic material layer 43away from the base layer 41. The bonding layer 45 defines a plurality ofreceiving areas 450, and each receiving area 450 is configured forreceiving one light emitting element 10. In the first electromagneticplate 30 shown in FIG. 3, the through holes 33 and the receiving areas450 correspond to each other in number and position.

In one embodiment, a control circuit (not shown) is further providedcorresponding to the second electromagnetic plate 50. The controlcircuit is configured to supply a voltage or current to the secondelectromagnetic plate 50 to make the second electromagnetic plate 50magnetic, thereby making the second magnetic material layer 43 of thereceiving substrate 40 magnetic. In addition, a magnetic strength of thesecond electromagnetic plate 50 can be controlled by adjusting amagnitude of the voltage or current applied to the secondelectromagnetic plate 50 by the control circuit, thereby a magneticstrength of the second magnetic material layer 43 of the receivingsubstrate 40 can be controlled.

In one embodiment, the receiving substrate 40 is a thin film transistor(TFT) substrate. The bonding layer 45 includes a TFT array layer 451 ona side of the second magnetic material layer 43 away from the base layer41 and a pixel defining layer 452 on a side of the TFT array layer 451away from the base layer 41. The pixel defining layer 452 definescontact holes 453 each of which exposes the TFT array layer 451. Eachcontact hole 453 is defined as one receiving area 450.

In one embodiment, the base layer 41 may be made of a rigid material,such as glass, quartz, silicon wafer. In other embodiments, the baselayer 41 may be made of a flexible material such as polyimide (PI) orpolyethylene terephthalate (PET).

In one embodiment, the receiving substrate 40 further includes aninsulating layer 44 between the second magnetic material layer 43 andthe TFT array layer 451. The insulating layer 44 electrically insulatesthe second magnetic material layer 43 and the TFT array layer 451, toprevent the TFT array layer 451 from affecting the second magneticmaterial layer 43 during the transfer of the light emitting elements 10.The insulating layer 44 may be made of a silicon oxide (SiOx) layer, asilicon nitride (SiNx) layer, or a multiple layer including the siliconoxide (SiOx) layer and the silicon nitride (SiNx) layer.

In one embodiment, the receiving substrate 40 further includes a barrierlayer 42 between the base layer 41 and the second magnetic materiallayer 43, to prevent moisture, corrosive oxygen, and the like fromaffecting the properties of the second magnetic material layer 43 andthe TFT array layer 451. The barrier layer 42 may be made of a siliconoxide (SiOx) layer, a silicon nitride (SiNx) layer, or a multiple layerthereof including the silicon oxide (SiOx) layer and the silicon nitride(SiNx) layer.

As FIG. 5 indicates, the steps involved in the process of making the TFTsubstrate are: sequentially forming the barrier layer 42, the secondmagnetic material layer 43, and the insulating layer 44 on the baselayer 41. Then, forming the TFT array layer 451 and the pixel defininglayer 452, wherein the TFT array layer 451 includes a first buffer layer51, a second buffer layer 52, a plurality of TFTs 53 (only one isshown), a first interlayer dielectric layer 54, a second interlayerdielectric layer 55, an overcoat layer 56, and a plurality of contactelectrodes 57 (only one is shown).

In one embodiment, the first buffer layer 51, the second buffer layer52, the first interlayer dielectric layer 54, the second interlayerdielectric layer 55, and the overcoat layer 56 may be made of, such as asilicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, or amultiple layer thereof including the silicon oxide (SiOx) layer and thesilicon nitride (SiNx) layer. The contact electrode 57 may be made of anon-magnetic conductive material, such as indium tin oxide (ITO), indiumzinc oxide (IZO), and zinc oxide (ZnO).

As shown in FIG. 5, each of the TFTs 53 includes a gate electrode GE, asemiconductor layer AS, a gate insulating layer GI, a source electrodeSE, and a drain electrode DE. The overcoat layer 56 defines a pluralityof vias 561, each via 561 exposes the drain electrode DE of one TFT 53.The drain electrode DE of each of the TFTs 53 is electrically connectedto a contact electrode 57 through one of the vias 561. The contact hole453 (receiving area 450) defined on the pixel defining layer 452 exposesthe contact electrode 57, for electrically connecting to one of thelight emitting elements 10.

In one embodiment, the gate electrode GE, the source electrode SE, andthe drain electrode DE may each be made of one or more of molybdenum(Mo), aluminum (Al), gold (Au), titanium (Ti), and copper (Cu). In otherembodiments, each of the gate electrode GE, the source electrode SE, andthe drain electrode DE is a multiple layer formed of one of molybdenum(Mo), aluminum (Al), gold (Au), titanium (Ti), neodymium (Nd), copper(Cu), or a combination thereof. For example, each of the gate electrodeGE, the source electrode SE, and the drain electrode DE can be formed asa double layer of Mo/Al. In one embodiment, the gate electrode GE, thesource electrode SE, and the drain electrode DE may be made ofnon-magnetic conductive materials. The gate insulating layer GI may bemade of a silicon oxide (SiOx) layer, a silicon nitride (SiNx) layer, ora multiple layer including the silicon oxide (SiOx) layer and thesilicon nitride (SiNx) layer. The semiconductor layer AS may be made ofa silicon semiconductor or an oxide semiconductor.

In one embodiment, the TFT substrate defines a plurality of pixels, andeach pixel includes sub-pixels emitting light of different colors. Eachsub-pixel corresponds to one light emitting element 10.

In one embodiment, each pixel includes a red (R) sub-pixel, a green (G)sub-pixel, and a blue (B) sub-pixel. The R, and B sub-pixels eachcorrespond to one light emitting element 10 emitting red, green, andblue light, respectively.

In other embodiments, each pixel may include R, B and W (white)sub-pixels. The W sub-pixel corresponds to one light emitting element 10emitting white light. Each pixel may further include multi-colorsub-pixels, and each multi-color sub-pixel corresponds to one lightemitting element 10 emitting multiple colors.

In one embodiment, the second magnetic material layer 43 is arrangedover an entire surface. That is, the coils 4311 are not only arranged tocorrespond to the receiving areas 450, but are also arranged tocorrespond to positions between adjacent receiving areas 450.

In another embodiment, as shown in FIGS. 5 and 6, the second magneticmaterial layer 43 is not arranged over the entire surface. The secondmagnetic material layer 43 includes a plurality of electromagnetic units431 spaced apart from each other. Each electromagnetic unit 431corresponds to at least one receiving area 450.

As shown in FIG. 6, each electromagnetic unit 431 corresponds to onereceiving area 450. A projection of each electromagnetic unit 431 on thebase layer 41 completely covers a projection of its receiving area 450on the base layer 41. That is, each electromagnetic unit 431 is arrangedto correspond to one sub-pixel.

As shown in FIG. 7, each electromagnetic unit 431 corresponds to andaligns with three adjacent receiving areas 450. The projection of eachelectromagnetic unit 431 on the base layer 41 completely covers theprojection of the corresponding three receiving areas 450 on the baselayer 41. That is, each electromagnetic unit 431 is arranged tocorrespond to three or more than three sub-pixels.

A shape of each electromagnetic unit 431 is not limited, for example, itmay be circular as shown in FIG. 6 or rectangular as shown in FIG. 7.

Block S14: the first electromagnetic plate 30 as shown in FIGS. 8through 10 is energized to magnetically adsorb one light emittingelement 10 from the carrier substrate 20 at each adsorption position 32.A surface of the first electromagnetic plate 30 on which the lightemitting elements 10 are magnetically adsorbed is opposite to a surfaceof the receiving substrate 40 defining the receiving areas 450, and thelight emitting elements 10 are aligned one-to-one with the receivingareas 450.

As shown in FIG. 8, the first electromagnetic plate 30 is moved abovethe carrier substrate 20, and the through holes 33 are alignedone-to-one with the light emitting elements 10 on the carrier substrate20, each of the through holes 33 is aligned with one of the lightemitting elements 10.

As shown in FIG. 9, after the through holes 33 and the light emittingelements 10 are aligned one by one, the control circuit in the firstelectromagnetic plate 30 is turned on, and a voltage or current isapplied to the first electromagnetic plate 30 by the control circuit.When the voltage or current is applied to the first electromagneticplate 30, the first electromagnetic plate 30 generates magnetismopposite to the magnetic pole of the first electrode 11 (i.e., firstmagnetic material layer 16) of each light emitting element 10.

As shown in FIG. 10, the light emitting elements 10 on the carriersubstrate 20 are attracted to the corresponding through holes 33 due tothe magnetic force between the light emitting element 10 and the firstelectromagnetic plate 30. Each position of the first electromagneticplate 30 corresponding to each through hole 33 can adsorb one lightemitting element 10. The positions of the first electromagnetic plate 30having no through holes 33 do not absorb any of the light emittingelements 10 due to the insulating non-magnetic material layer 31.

After the first electromagnetic plate 30 corresponding to the positionof each through hole 33 adsorbs one light emitting element 10 as shownin FIG. 10, the first electromagnetic plate 30 remains energized, andmoves over the receiving substrate 40, so that each of the lightemitting elements 10 adsorbed on the first electromagnetic plate 30 isaligned one-to-one with the corresponding receiving area 450 on thereceiving substrate 40.

Block S15: A second electromagnetic plate 50 is provided as shown inFIG. 11. The second electromagnetic plate 50 is on a side of the baselayer 41 away from the second magnetic material layer 43. The secondelectromagnetic plate 50 will have magnetic properties after beingenergized.

Block S16: the second electromagnetic plate 50 is powered on to form amagnetic field between the first magnetic material layer 16 of eachlight emitting element 10 and the second magnetic material layer 43, andthe first electromagnetic plate 30 is powered off so that each of thelight emitting elements 10 is detached from the first electromagneticplate 30 by the magnetic field and transferred to a correspondingreceiving area 450 of the receiving substrate 40.

After aligning each light emitting element 10 adsorbed on the firstelectromagnetic plate 30 with the corresponding receiving area 450 onthe receiving substrate 40, as shown in FIG. 11, the firstelectromagnetic plate 30 is moved toward the receiving substrate 40 sothat each light emitting element 10 abuts and contacts the correspondingreceiving area 450. At the same time, the second electromagnetic plate50 is powered on to make the second magnetic material layer 43 of thereceiving substrate 40 magnetic. A magnetic force between the firstmagnetic material layer 16 of each light emitting element 10 and thesecond magnetic material layer 43 is generated. As shown in FIG. 13, thefirst electromagnetic plate 30 is powered off, and each of the lightemitting elements 10 and its first and second electrodes 11 and 15 aredetached from the first electromagnetic plate 30 under the magneticfield and transferred to the corresponding receiving area 450. Then, thefirst electromagnetic plate 30, the insulating nonmagnetic materiallayer 31 and the second electromagnetic plate 50 are removed.

In the method, a color of light emitted from each light emitting element10 is not limited. In this method, after the first electromagnetic plate30 is energized, the surface of the first electromagnetic plate 30 canmagnetically adsorb a large number of light emitting elements 10 at onetime, thus transfer of a large quantity of light emitting elements 10 isachieved.

In one embodiment, when the second electromagnetic plate 50 is poweredon a magnetic force between the first magnetic material layer 16 of eachof the light-emitting elements 10 and the second magnetic material layer43 is generated. Therefore, after the first electromagnetic plate 30 ispowered off, each of the light emitting elements 10 is magneticallyattracted by the second magnetic material layer 43 in the correspondingreceiving area 450 of the receiving substrate 40 in addition togravitational attraction. In addition, interference from magnetic linesof force around the receiving area 450 can be avoided, thereby avoidingthe problem of displacement of the light emitting elements 10 during thetransfer process. The alignment accuracy of the light emitting elements10 is improved, and the transfer error is reduced.

Referring to FIG. 14, a flowchart of a method for making a display panelin one embodiment is disclosed. Each block in this method represents oneor more processes, methods, or subroutines, carried out in the method.Additionally, the illustrated order of blocks is by example only and theorder of the blocks can change. The method can begin at Block S21.

Block S21: the light emitting elements 10 are provided.

Block S22: the first electromagnetic plate 30 is provided.

Block S23: the receiving substrate 40 is provided.

Block S24: the first electromagnetic plate 30 is energized tomagnetically adsorb one light emitting element 10 at each adsorptionposition 32.

Block S25: the second electromagnetic plate 50 is provided.

Block S26: the second electromagnetic plate 50 is powered on to form amagnetic field between the first magnetic material layer 16 of eachlight emitting element 10 and the second magnetic material layer 43, andthe first electromagnetic plate 30 is powered off so that each of thelight emitting elements 10 is detached from the first electromagneticplate 30 by the magnetic field and transferred to a correspondingreceiving area 450 of the receiving substrate 40.

Blocks S21 to S26 are the same as Blocks S11 to S16 above, and will notbe described here.

Block S27: a planarization layer 60 is formed on a side of the pixeldefining layer 452 away from the base layer 41.

As shown in FIG. 15, the first electrode 11 of each light emittingelement 10 is electrically connected to the TFT array layer 451 throughone contact electrode 57, and the planarization layer 60 fills gapsbetween adjacent light emitting elements 10 and exposes the firstelectrode 11 of each light emitting element 10.

Block S28: a common electrode layer 70 is formed on the planarizationlayer 60.

As shown in FIG. 16, the common electrode layer 70 is electricallyconnected to the first electrode 11 of each of the light emittingelements 10. The common electrode layer 70 may be connected to a drivingcircuit (not shown) through wires to apply a voltage to the firstelectrode 11 of the light emitting element 10. When there is a forwardbias between the first electrode 11 and the second electrode 15 of thelight emitting element 10, the light emitting element 10 emits light.

Block S29: as shown in FIG. 17, an encapsulating layer 80 is formed on aside of the common electrode layer 70 away from the planarization layer60, thereby obtaining the display panel 100.

In one embodiment, the light emitting elements 10 provided in Block S21are light emitting elements emitting light of the same color, such aslight emitting elements emitting red light, light emitting elementsemitting green light, light emitting elements emitting blue light, etc.,thereby the display panel 100 would be a monochrome display panel. Themonochrome display panel 100 can be applied to advertising signs,indicator lights, and the like.

In one embodiment, the light emitting elements 10 provided in Block S21are light emitting elements emitting light of different colors, thedisplay panel 100 is thereby a color display panel. The color displaypanel 100 can be applied to mobile phones, tablet computers, smartwatches, and the like.

It should be noted that the second magnetic material layer 43 is onlyused in the process of transferring the light emitting element 10 to thereceiving substrate 40. When the display panel 100 displays images, thesecond magnetic material layer 43 has no function, and the secondmagnetic material layer 43 and the TFT array layer 451 are electricallyinsulated by the insulating layer 44, so that the second magneticmaterial layer 43 does not affect the light emission from the lightemitting elements 10.

In one embodiment, a substrate using in a display panel is disclosed.The substrate is the receiving substrate 40, and will not be describedhere again.

In one embodiment, a display panel is disclosed. The display panel isthe display panel 100, and will not be described again here.

It is to be understood, even though information and advantages of thepresent exemplary embodiments have been set forth in the foregoingdescription, together with details of the structures and functions ofthe present exemplary embodiments, the disclosure is illustrative only.Changes may be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the present exemplaryembodiments to the full extent indicated by the plain meaning of theterms in which the appended claims are expressed.

What is claimed is:
 1. A method for transferring light emitting elements, comprising: providing a plurality of light emitting elements, wherein a first magnetic material layer is on an end of each of the plurality of light emitting elements; providing a first electromagnetic plate, wherein the first electromagnetic plate defines a plurality of adsorption positions, each of the plurality of adsorption positions is capable of magnetically attracting one light emitting element on being energized; providing a receiving substrate, wherein providing the receiving substrate comprises providing a base layer, forming a second magnetic material layer on a side of the base layer, and forming a bonding layer on a side of the second magnetic material layer away from the base layer, wherein the bonding layer defines a plurality of receiving areas, each of the plurality of receiving areas is configured for receiving one of the plurality of light emitting elements; energizing the first electromagnetic plate to magnetically adsorb one of the plurality of light emitting elements at each of the plurality of adsorption positions, wherein a surface of the first electromagnetic plate on which the plurality of light emitting elements are magnetically adsorbed is opposite to a surface of the receiving substrate defining the plurality of receiving areas, and the plurality of the light emitting elements are aligned one-to-one with the plurality of the receiving areas; providing a second electromagnetic plate on a side of the base layer away from the second magnetic material layer; wherein the second electromagnetic plate has magnetic properties after being energized; and powering on the second electromagnetic plate to form a magnetic field between the first magnetic material layer of each of the plurality of light emitting elements and the second magnetic material layer, and powering off the first electromagnetic plate so that each of the plurality of light emitting elements is detached from the first electromagnetic plate by the magnetic field and transferred to one corresponding receiving area of the receiving substrate.
 2. The method according to claim 1, wherein providing the receiving substrate further comprises patterning the second magnetic material layer to form a plurality of magnetic material units spaced apart from each other, and each of the plurality of magnetic material units is arranged to correspond to at least one of the plurality of receiving areas.
 3. The method according to claim 1, wherein forming the bonding layer further comprises forming a thin film transistor (TFT) array layer on a side of the second magnetic material layer away from the base layer and forming a pixel defining layer on a side of the TFT array layer away from the base layer, wherein the pixel defining layer defines a plurality of contact holes exposing the TFT array layer, each of the plurality of contact hole is defined as one of the plurality of receiving areas.
 4. The method according to claim 3, wherein forming the receiving substrate further comprises forming an insulating layer between the second magnetic material layer and the TFT array layer.
 5. The method according to claim 1, further comprising: forming an insulating nonmagnetic material layer on a surface of the first electromagnetic plate; and defining a plurality of through holes exposing the surface of the first electromagnetic plate in the insulating nonmagnetic material layer, wherein each of the plurality of through holes is defined as one of the plurality of adsorption positions.
 6. A method for making a display panel, comprising: providing a plurality of light emitting elements, wherein a first magnetic material layer is on an end of each of the plurality of light emitting elements; providing a first electromagnetic plate, wherein the first electromagnetic plate defines a plurality of adsorption positions, each of the plurality of adsorption positions is capable of magnetically attracting one light emitting element on being energized; providing a receiving substrate, wherein providing the receiving substrate comprises providing a base layer, forming an second magnetic material layer on a side of the base layer, and forming a bonding layer on a side of the second magnetic material layer away from the base layer, wherein, the bonding layer defines a plurality of receiving areas, each of the plurality of receiving areas is configured for receiving one of the plurality of light emitting elements; energizing the first electromagnetic plate to magnetically adsorb one of the plurality of light emitting elements at each of the plurality of adsorption positions, wherein a surface of the first electromagnetic plate on which the plurality of light emitting elements are magnetically adsorbed is opposite to a surface of the receiving substrate defining the plurality of receiving areas, and the plurality of the light emitting elements are aligned one-to-one with the plurality of the receiving areas; providing a second electromagnetic plate on a side of the base layer away from the second magnetic material layer, wherein the second electromagnetic plate has magnetic properties after being energized; and powering on the second electromagnetic plate to form a magnetic field between the first magnetic material layer of each of the plurality of light emitting elements and the second magnetic material layer, and powering off the first electromagnetic plate so that each of the plurality of light emitting elements is detached from the first electromagnetic plate by the magnetic field and transferred to one corresponding receiving area of the receiving substrate.
 7. The method according to claim 6, wherein providing the receiving substrate further comprises patterning the second magnetic material layer to form a plurality of magnetic material units spaced apart from each other, and each of the plurality of magnetic material units is arranged to correspond to at least one of the plurality of receiving areas.
 8. The method according to claim 6, wherein forming the bonding layer further comprises forming a thin film transistor (TFT) array layer on a side of the second magnetic material layer away from the base layer and forming a pixel defining layer on a side of the TFT array layer away from the base layer, wherein the pixel defining layer defines a plurality of contact holes exposing the TFT array layer, each of the plurality of contact hole is defined as one of the plurality of receiving areas.
 9. The method according to claim 8, wherein forming the receiving substrate further comprises forming an insulating layer between the second magnetic material layer and the TFT array layer.
 10. The method according to claim 8, wherein forming the TFT array layer comprises forming a plurality of thin film transistors (TFTs), each of the plurality of light emitting elements having a first electrode and a second electrode, the first electrode of each of the plurality of light emitting elements is electrically connected with one of the plurality of TFTs.
 11. The method according to claim 10, after each of the plurality of light emitting elements is detached from the first electromagnetic plate by the magnetic field and transferred to a corresponding receiving area of the receiving substrate, the method further comprising forming a planarization layer on a side of the pixel defining layer away from the base layer, and the planarization layer fills a gap between adjacent two of the plurality of light emitting elements and exposes the second electrode of each of the plurality of light emitting elements.
 12. The method according to claim 11, further comprising forming a common electrode layer on a side of the planarization layer away from the pixel defining layer, wherein the common electrode layer is electrically connected to the second electrode of each of the plurality of light emitting elements. 